The invention relates generally sheaths for use with interventional devices within a body. More particularly, the invention relates to a sheath, which is substantially transmissive of ultraviolet and/or visible light, for use with an interventional device for tissue spectroscopy within a body.
Tissue spectroscopy, which can include optical biopsy procedures, is a relatively new field in which light waves are used to diagnose diseases in the human body. Systems for performing such procedures typically include one or more light sources that illuminate the tissue and one or more receiving channels that measure or map the resulting emission from illuminated tissue. Interventional devices for performing such procedures can take on many forms. A common form is a long fiber-equipped catheter with a proximally mounted connector and a distal tip that is capable of sending and receiving light through optical transmission. Another form is a probe, which can contain a light source and detector, that can be placed in a body cavity. Examples of such probes are provided in commonly owned, copending U.S. patent application entitled, xe2x80x9cMiniature Spectrometerxe2x80x9d by Robert J. Crowley, Ser. No. 08/898,604, which is incorporated herein by reference. Within these probe-style spectroscopic devices, it is possible to include an entire power supply, light emission system, light detection system, and readout within the device. Such probes can be disposable using mass production techniques.
There are, however, situations in which repeated use of the probe is desirable. Such situations can include calibration, test and application of the probe to various areas of the body. The related problems of probe contamination and disease transfer should be avoided whenever possible. It has been suggested that condoms can be used as a sheath over such probes to prevent the occurrence of these problems. One problem associated with condoms and many other known sheath materials is that they often attenuate energy in the diagnostic wavelength bands, including the visible and ultraviolet wavelength ranges that are useful for detecting cancer and other life threatening diseases.
It is therefore an object of the present invention to provide a sheath for use with an interventional device which is substantially transmissive of wavelengths used in tissue spectroscopy. It is another object of the invention to provide a sheath shaped to provide optimal optical contact with tissue under examination while affording good light transmission characteristics. It is yet another object of the invention to provide a sheath that can be contoured using a pressurizable fluid so that optimal contact with various tissue and organs shapes can be achieved. It is yet another object of the invention to provide a sheath with an optically transmissive distal end constructed to provide better transmission capability and to provide a filter function to enhance the spectroscopic procedure.
In one aspect, the present invention features a sheath for use with an interventional device for diagnostic procedures in a body. The interventional device can include, without limitation, a catheter, an endoscope, a guide wire, a needle or an introducer. The diagnostic procedures can include tissue spectroscopy or, more specifically, in vivo optical biopsy procedures.
The sheath comprises a flexible body having an open proximal end and a closed distal end. The sheath can be cylindrically shaped to securely receive the interventional device via an interference fit. At least the distal end of the flexible body is formed of a material substantially transmissive of ultraviolet and/or visible light. The material can be, for example, a polymeric material such as polyurethane, polyethylene or polystyrene. A quartz window, which is substantially transmissive of ultraviolet and/or visible light, can be disposed on the distal end of the flexible body. The sheath can be disposable.
In a detailed embodiment, the sheath can also comprise a fluid chamber and a channel. The fluid chamber is located at the distal end of the flexible body. The channel extends from the proximal end to the distal end of the flexible body and provides fluid to the fluid chamber. The fluid chamber can be filled to provide optimal optical contact between the interventional device and the tissue under examination. The distal end of the flexible body can be formed of a material and/or have a thickness optimized to selectively filter energy emitted from tissue in the body at predetermined wavelengths (e.g., below 280 nm and above 500 nm)
In another aspect, the invention features an interventional device for tissue spectroscopy and in vivo optical biopsy procedures. The device includes an endoscopic probe and a sheath. The probe is insertible into an orifice of a body. The sheath comprises a flexible body having an open proximal end and a closed distal end. At least the distal end of the flexible body is formed of a material substantially transmissive of ultraviolet and/or visible light (e.g., polyurethane, polyethylene or polystyrene). A quartz window can be disposed on the distal end of the flexible body. The sheath can also comprise a fluid chamber and a channel for providing optimal optical contact between the interventional device and the tissue under examination.